stouffer etal



R. c. STOUFFER ET AL 2,525,626

RIVET-STEM GRIPPING AND PULLING MECHANISM Oct. 10, 1950 5 Sheets-Sheet 1 Filed Dec.

Oct. 10, 1950 R. c. STOUFFER ETAL 2,525,626

RIvET-STEM GRIPPING AND PULLING MECHANISM 5 Sheets-Sheet Filed Dec. 29, 1945 Q Q NE \K WW 5 E mm X m xxx wk Oct. 10, 1950 R. c. sTouFFEfi ET AL RIVET-STEM GRIPPING AND PULLING MECHANISM 5 Sheets-Sheetfi Filed Dec. 29, 1945 Patented Oct. 1 0,

RIVET-STEM GRIPPING AND PULLING MEGHANISM RayC. StoiiffenB-uffalo, Ni Ye,- and HerbertWL Stouffer, Fort Erie, Ontario, Ganada Application December 29, 1945. Serial No. 638,094

2 i Claims.

This invention relates to*a tool for usein-setting or fixing pierced or tubular rivets, of the kindi-n which the rivet is mounted on a mandrel having an enlarged head so that, when the rivet is inserted in position, by thrusting upon the end of the rivet and simultaneously pulling upon the mandrel the head. of the mandrel causes the rivet to expand andupset. While the stem of the mandrel can be threaded toreceive a nut or otherwise adapted forsecuring attachments; or may be cut on or pushedback, the mandrel for which the present tool is particularlyadapted has its head torn from the stem of the mandrel in expanding the rivet, the stem being drawn through the rivet by the tool and the head falling back. i

One of the principal objects of-the invention is to provide such a tool which operates ir-ompneumatic pressure, and atthe same time is compact and light in weight sothatit is convenient to. use as a manual tool.

Another object is to provide such 9, pneumatic tool which embodies an air cushion for the impact resulting from the tearing of the headof the mandrel from thestem thereof.

Another object is to provide such a pneumatic tool in which provision is -made for utilizing the pneumatic pressure to blow the stemof the mandrel from. between the jaws of the tool so that the tool is immediately placedin condition for application to another rivet.

Another object of theinvention is to provide:

such a pneumatic tool which is relativelylongand slender so as to be. capable of easyhandling, this being accomplished. in the present invention by the provision of a multiple of pistons arranged in tandem.

Another purpose is to providesuch atool hav-- ing simple and readily operable valving for introducing and relieving the pneumatic pressure;

Another aim of the invention is to provide a positive release for both of the jaws which. grip the mandrel and which spreadsthe jaws for the reception of the mandrel of another. rivet.

Another aim is to provide, in such a tool, low cost and readily replaced gripping faces for the jaws which seize the mandrel. i

Another aim of the inventionis to provide simple one-piece. yoke which carries the jaws and the parts associatedtherewith.

In the accompanying drawings:

Fig. 1 is a top plan view, with parts broken away, of a rivetingtoolembodying the present invention.

Fig. 2 is a side, elevation thereof, withparts broken away.-

Fig; 3'is amendelevation'thereof.

Fig. 4*is an opposite endelevation thereof;-

Fig. 5 through the tool, this section being taken on line 5-5, Fig; 2.

Figs. 6-and 7 are vertical transversesections, taken on the correspondingly numbered lines of Fig; 2.

Fig. 8--is afragmentary vertical longitudinalsection, taken on line B -8; Fig. 1.

Fig. 9- is-a view similar to Fig. 8 showing another position of the valve.

Fig. 10 is a fragmentary enlarged view similar tqFig. 5 and showing the parts in positionabout toseize the mandrel for expanding the -tubu-lar rivet.

Fig. 11 is -a-view similar to Fig-.; 10 showing the". mandrel seizedby the jawsof the tooland drawn to upset or'expand the tubular rivet.

Fig. 1215 a fragmentary view-simi1ar to Figs. 10 and ll and showingthebroken off stemof the mandrel beingejected from between the jaws ofthe tool by air pressure.

Fig. l3-is a vertical transverse section, taken on line 13-43, Fig. 1-1.

The toolincludes three cylinders IS arranged:

coaxially-= and separated by intermediate: cylinder heads. lfi and la and having outer endheads l9". and 2ill Theseccylindersand end heads oan be secured together any suitable manner as by the foure tie bolts zl shown which: extend through all of the cylinderheads and hold the multiple? cylinder structure in assembled: relation.

These cylinder heads [6, ltlugnd 20 are provided with coaxiatcentral bores in which apiston rod 22: is arrangeds Withineach of the cylinders l5 a piston- 23- -of anysuitable character is mountedon-thepiston rod 22. These pistons can be securecl to-the piston rod in any suitable manner and -are shown as secured by an end nut zd on -the pistonrod and a seriesof sleeves 25 each slidingly mounted in the: central bore of the correspendingcylinder head l5, I8 and 20, these sle'eves serving to-space the pistons. 23 and the s1eeve 25 'withinthe-cylinder head 20 being heldby a nutzfi and lock nut 28 provided ontheexternalthrealded end 28 0f the pistonrod 22; It willflbe seen that through th sleeves 25 the pistons 23 are securedat spaced intervals by the end nuts 24 and 26.

Secured by screws 1 30 to the outer face end head fln isaplate 3| which is -shown as being octagonalinshape and which has a central opening 32 surrounding the projecting-end-of the pisis ahorizontal longitudinal section of the ton rod ZZJ T02 this plate are secured-the legs: 33iof a yokew34 this-woke extending horizontally outward from the multiple cylinder Structure coaxially therewith. This yoke is secured to the anchoring plate 3| by a pair of screws 35 which extend through the end cross bar 36 of the yoke E i and along the inner sides of the legs 33 thereof. The threaded ends of these screws 35 screw into threaded openings 38 provided in the anchoring plate 3 l.

Within the yoke 34", is slidingly mounted a slide 453 having opposite semi-cylindrical slideways t! which engage the screws 35. To facilitate construction the yoke 34 and slide ll} are preferably made from a single block of metal, this block being drilled to provide the holes for the screws and this block then being sawed along these drilled holes and transversely at the cross bar 35 of the yoke so as to separate the slide 40 from the yoke 35 and at the same time'insure a proper fit between the screws 35 and both the yoke 34 and the slide ifi. internally threaded bore 43 at one end in which the threaded end 29 of the piston rod is screwed.

This slide is provided with a chamber 45 which is rela ively wide at its rear end and at its front end is provided with converging wedging faces 48 leading to an opening 58 at the extremity of the slide opposite from the'oylinder structure. For accessibility to the parts within this chamber the rear end of the chamber 45 is open at its upper and lower sides and provided with cover plates fitted therein. These cover plates are held by a tubular sheet metal sleeve Ell which is rectangular in cross section and which is fitted over the yoke 3d from the outer end thereof. Within the chamber d5 is arranged a pair of jaws 52, these jaws being in the form of blocks of metal, the upper and lower faces of which fit the upper and lower walls of the chamber 55, these upper and lower walls of the chamber 45 being in part provided by the cover plates 39 and in part provided by the cross pieces 53 which provide the opening 18 at the end of the slide. These jaws 52 are provided with opposed recesses 55 which are generally rectangular in shape and each of which receives an oblong mandrel gripping member 53. The purpose of these oblong gripping members 56 is to provide readily removable gripping surfaces to engage the mandrel, and sections of a square file have been found to be of low cost and entirely satisfactory for this purpose.

Each of the jaws 52 is provided with a wedge face 58 which conforms to and engages the corresponding wedge face 45 of the slide &8. At its opposite end each of these jaws 52 is provided with wedge faces 59 which face convergingly toward each other and are engaged by the conforming faces til of a wedge-shaped follower 8!. This follower is provided with a central bore 62 in which is fitted a tube 63 mounted in the slide ell coaxial with the multiple cylinder structure. The follower 6! is urged into engagement with the jaws 52 by a plurality of helical compression springs 65 one of which surrounds the tube 63 and the other two of which are arranged on opposite sides thereof. Attheir outer ends the jaws 52 are provided with opposed wedge-shaped faces 56 which diverge outwardly toward the ends of the jaws. These wedge-shaped faces 66 cooperate with wedge-shaped faces 58 provided in the enlarged central part of the end cross bar 36 of the yoke 34. This enlarged central part of the end cross bar 36 als carries a bushing 'lll, this bushing being screwed therein and forming a tubular thrust member having a head H at its This slide is provided with an L 4 forward end which engages the tubular rivet as hereinafter described. This bushing or tubular thrust member has a bore which receives the mandrel and can be replaced with a bushing having a different sized bore to receive a diiferent sized mandrel.

This tubular thrust member ll] is fitted against the flange T2 at one end of the tubular rivet E3, the other end of this tubular rivet being left unflanged so that it can be inserted into register ing openings provided in the pieces i l to be riveted together. The flanging of the opposite end of the tubular rivet i3 is effected by a mandrel '56 having a stem 73 which is gripped by the mandrel gripping members 55 and is provided with a head 79 which is torn from the stem of the mandrel in expanding the tubular rivets 13,

as indicated by dotted lines in Fig. 11.

The slide so is reciprocated along the screws 35 pneumatically. For this purpose a sliding cylindrical control valve indicated generally at 80 is secured to the rear end of the multiple cylinder structure and is connected to an air pressure line 83 and provided with a vent 82. This valve comprises a valve body 83 which is shown as secured to the outer face of the end head l9 by screws 84 (Fig. 9) and as having a sliding valve cylinder 85 slidingly fitted in a sleeve 36 arranged in a bore 38 in the valve body 83, this bore being shown as coaxial with the multiple cylinder structure. The inner-end of the sliding valve cylinder 85 is shown as flanged outwardly, as indicated at 39, to fit the end of the sleeve 86 and a helical compression spring 9G is arranged in the bore 88 and interposed between the cylinder head l9 and the flanged end 89 of the sliding valve cylinder 85 so as to urge this valve head 35 outwardly. The opposite end of the sliding valve cylinder 85 is provided with a push stem 5:! slidingly fitted in a bonnet 92, this bonnet being fitted in the outer end of the bore 39 and secured in place by a set screw 93 or in any other suitable manner. The push stem Si for the valve is provided with a head at and the stem 9| and sliding cylindrical valve 85 can be held against turning by a pin 95 secured to one side of the head 94 and sliding in a bore 96 provided axially in the bonnet $2.

The sliding valve cylinder 35 is provided in its periphery with an outer annular groove 98 and an inner annular groove $9. This valve stem is additionally provided with a passage 666 leading from a port 5 ll! in the upper side of its periphery to the inner end of the bore 88 in the valve body, this inner end of the bore 38 being vented through the vent opening 82, as shown in Fig. 2. The air pressure supply pipe 8i leads to a chamber 33 in the bottom of the valve body 8i and the sleeve 86 is provided with a pair of ports I04 and m5, the port Mi l establishing communication between the air pressure supply chamber I03 and the annular groove 98 of the sliding valve cylinder when this sliding valve cylinder is positioned inwardly, as illustrated in Fig. 8, and the port Hi5 establishing communication between the air pressure supply chamber Ni? and the annular groove Q9 of the sliding valve cylinder when the valve is released, as shown in Fig. 9.

In the depressed position of the valve, illustrated in Fig. 8, the annular groove 98 in the sliding valve cylinder 85, in addition to being in communication with the air pressure supply chamber H33 through the port I 04 is also in communication with a passage Hi6 which extends through the valve body and into the end head I 9 and communicates with a bore 191 surrounding the lower right hand (Fig. 6) tie bolt 2|. Between the cylinder heads l9, I6, I8 andZllthis tie bolt is surrounded by sleeves I58 which have airtight fit with these cylinder heads I9, I6, I8 and 20 and which provide an air passage I09 extending the full length of the multiple cylinder structure. This air line is connected by a branch passage H in each of the cylinder heads I6, IB and 26 with the corresponding cylinder, these passages communicating with the forward ends of the several cylinders so that when air pressure is introduced therethrough the pistons 23 are moved rearwardly.

In the released position of the valve, illustrated in Fig. 9, the annular groove 99 in the sliding valve cylinder 85, in addition to being in communication with the air pressure supply chamber I03 through the port I is also in communication with a passage III which extends through the valve body and into the end head I9 and communicates with a bore H2 surrounding upper left hand (Fig. 6) tie bolt 2I. Between the cylinder heads I9, I5, I8 and this tie bolt is surrounded by sleeves H3 which have airtight fit with these cylinder heads I9, I6, I8 and 2t and which provide an air passage H4 extending the full length of the multiple cylinder structure. This air line H4 is connected by a branch passage II5 in each of the cylinder heads I6 and I8 with the corresponding cylinder, these passages communicating with the rearward ends of these cylinders. In addition a restricted passage H6, provided in a screw bushing III, as shown in Figs. 8 and 9, establishes direct communication between the passage Ill and the adjacent cylinder. It will therefore be seen that when air pressure is introduced into the passage III this pressure is impressed through the passage H6 and through the passage H4 and branches [I5 on the rear sides of the pistons 23 so as to drive them forwardly. The restricted size of the .passage IIB cushions the reaction of the tool when the mandrel head breaks, as hereinafter described.

In either position of the sliding valve cylinder 85, when one of. the passages I06 or III is soin communication with the air pressure supply chamber I63, the other of these passages is in communication with the passage I05 leading to the vented inner end of the bore 88.

A feature of the invention also resides in the provision of means for blowing the severed stem 78 of the mandrel I5 from the tool after the riveting has been completed. To this end the piston rod 22 is provided with a passage I26 cornmunicating at one end with the interior of the tube 63 and at its opposite end with the interior of one of the cylinders I5.on the rear side of the corresponding piston 23, as best shown in Fig. 5.

In addition the follower 6| is provided with a passage I2I in line with the stem I8 of the mandrel held between the jaws 52 and communicating with the interior of the tube 63.

In the operation of the tool the mandrel I6 is first inserted in the tubular rivet 13 with its head I9 in engagement with the unflanged end of this tubular rivet. The unflanged end of this rivet I3 is then inserted in the registering openings of the pieces I4 to be riveted together. The tool operates to thrust against the flange 12 of the tubular rivet 13 and at the same time to pull upon the stem '18 thereof. This action forces the head I9 of the mandrel against the unflanged end of the tubular rivet 13, thereby to expand or upset a flange upon the unflanged end thereof.

61 The tool also operates to exert sufiicient pressure upon themandrel I6 to tear the head 19 from its stem I8, this head falling, as indicated by dotted lines in Fig. 11, the stem being retained by the tool.

To accomplish this result, after the assembled tubular rivet I3 and its mandrel 16 have been insertedin the pieces 14 to be rivetted together, the tool is brought with its tubular thrust member ID against the flange I2 of the rivet, the stem 18 of the mandrel being received in this tubular thrust member I0 and being disposed between the mandrel gripping members 56 carried by the jaws 52.

With the tool in this position the valve head 94 is pressed inwardly against the resistance of the helical spring to the position shown in Fig. 8. Inthis position air pressure from the supply line 8I passesthrough the chamber I03, port I04 in thesleeve B6, annular groove 98 in the sliding valve cylinder 85, passage I06 in the valve body 63 and cylinder head I9, passage I09 through the several sleeves I08 surrounding the lower right hand (Fig. 6) tie rods 2| and branch passage III] in each of the cylinder heads I6, I8 and 20.

These branch passages I I0 impress this pressure on the forward side of each of the pistons 23 thereby to move these pistons and their piston rod 22 rearwardly. This piston rod 22 is connected with the slide 40 and this movement of the piston rod moves this slide along the screws 35 from the position shown in Fig. 10 to the position shown in Fig. 11.

The rearward movement of the slide 45 operates to effect the movement of the jaws 52 toward each other as well as the rearward movement thereof. Thus, the springs 65 acting against the follower 6| urge the jaws 52 into engagement with the opposing cam faces 46 of the slide 46 and also into engagement with the cam faces 68 of the end,

of the jaws 52 is possible and hence the'con--v tinued rearward movement of the slide 40 causes the jaws 52 to move rearwardly with the slide. Since these jaws are in gripping engagement with the stem of the mandrel 16 a rearward pulling force is applied to the mandrel. Since the tubular rivet I3 is held against the tubular thrust member 10, this rearward pulling movement of the mandrel draws the head 19 of the mandrel against the unflanged end of the tubular rivet l3, thereby to expand a flange or head on this unflanged end of this rivet. The continued rearward movement of the mandrel I6 causes thehead I9 to be ruptured from the stem 18 of the mandrel, this head fallingfree, as indicated by dotted lines in Fig. 11.

This results, of course, in a sudden release of the slide 60 and its' jaws gripping the stem of the severed mandrel and a feature of the invention resides in the fact that this movement of theslide, immediately following the severance of the head I9 of the mandrel and release of its stem,

16 is cushioned. Thus, while the forward sides.

of the pistons 23.. are under air pressure, as just; 

